Executive functions are the cognitive abilities underlying our goal-directed behaviors. Among them, inhibitory control is defined as our ability to control our feelings, cognitions, and behavioral responses. As such, inhibitory control allows us to override a strong internal predisposition or external attraction that may lead to inappropriate task performance. Inhibitory control deficits have been proposed as a potential risk factor for depression, as those with lower inhibitory control may struggle to control their negative cognitions and emotions. However, our inhibitory control capacity is not stable and may fluctuate daily depending upon various factors. Here, we examined the everyday association between inhibitory control and mood among typical adults with various levels of depressive symptoms.

Participants (N=106) reported their depressive symptoms and completed a Go-NoGo (GNG) task measuring inhibitory control at baseline. They then completed a 5-day ecological-momentary-assessment (EMA) protocol using a mobile app developed by our lab, in which they reported their current mood and performed a shortened GNG task twice/day. Depressive symptoms were measured again following the EMA.

We found that individuals with elevated depressive symptoms demonstrated worse and more variable inhibitory control performance over the 5-day EMA sessions. In addition, the variability of inhibitory control across the 5 days contributed to the prediction of depressive symptoms. Moreover, reduced momentary inhibitory control was associated with more negative mood only for those with lower depressive symptoms. These findings suggest that variable, rather than mere reduced, inhibitory control, is related to depressive symptoms. These findings have implications for the prediction and potential treatment of depressive symptoms.